Focusing apparatus for enlargers



May 10, 1949. J, EAGLE 2,469,685

FOCUSING APPARATUS FOR ENLARGERS 2 Sheets-Sheet 1 Filed March 26, 1948JOHN/1'. EAGLE INVENTOR ATTORNEYS BY mzw May 10, 1949. J, EAGLE2,469,685

FOCUSING APPARATUS FOR ENLARGERS Filed March 26, .1948 '2 Sheets-Sheet 2ATTORNEYS Patented May 10, 1949 UNITED STATES PATENT "OFFICE FOCU'SINGAPPARATUS FOR EN-LARGERS John H. Eagle, Rochester, N. Y..,'assignor toEastman Kodak Company, Rochester, N. Y., a corporation of New JerseyApplication Marchl26, 1948, Serial No. 17,227

- 8 Claims.

This .invention .relates to photography and more. particularlyito.focusing apparatus for enlargers. One object .ofmy invention is toprovide a simple. construction which islight in weight,..accur.a.te in,use,..and relatively inexpensive to. build. .Another object of myinvention is to provide a, devicev of the class described which doesnot-require that .the various parts be made with ahighdegree .ofaccuracy .to work satisfactorily. Anotherobject .of my invention is .toprovide a focusing device for enlargerssupported by a-.single..p.ost .sothat it may be swung about the ,post; the parts being .so. designed thatthey will operate inany positionto which the mechanism is swung. .Afurther .object of my invention is to provide-asimple .type' of focusingmechanism whichcan be. quickly moved to approximately the. correctposition, and to provide a device in which there-is. afine adjustmentfor accurately finishing the focusing movement. Other objects willappear. from. the .following specification, thenoVel features beingparticularly pointed .out inthe .claims at. the endthere- .of.

. Coming .now tothe drawings wherein likerefer- .ence characters denotelikev ,parts throughout:

Fig. .1 is aiperspective view of a typical enlarging machine'equippedwith a focusing apparatus constructed in accordance with a.preferredform .of my invention;

Fig. 2 is an enlarged vfragmentary side relevation showing aportiondofthe focusing mechanism used in the enlarger :shown .in Fig. .1;

Fig. 3 is an enlarged fragmentary viewpartially insection showing. afocusing wheel, or spoQLengaging the supporting pallet;

"Fig. 4 is a fragmentary top plan view of the focusing.mechanismqemployed for moving the lens carriage;

-:Fig. 5 is v.an'enlarged fragmentary rear elevation of the main supportangular-adjusting mechvanism; and

Fig. 6 is. a topaplan view, .partially insection, of the slideblock-portion of the focusing mechanism.

.;Intheembodiment shownin the drawings, an enlarger may include a baseit which is preter ably made of 'metal shavingla topwall 2 and. a bottomWall 3 connected by side walls 4 and 5. .I'hisbox-like structure may beemployed as a paper .holderand. supports an upright post. 6 which ispreferablymade .of relatively light, inbularmaterial anchoredin .the topand bottom walls l and 3 oft-he .basemember.

..-Slidably--mounted on this tubular. post .6 is a 2 carriage which ispreferably formed 'of a pair of similar spaced "frames land '8; thetwoframes being of like *shape an-d being-preferably--made four-sided,as shown. Each frame has a pair of parallelsides 9 spacedfromthe 'post-6 and a pair of parallel sides 10 adjacent 'to the' post. The framemembers i and -8 are preferably-made by forming a single rod,or, ifextreme'lightness is required, a single tube into the shape shown; theends H and 12 of 'e'a'chirame member being fastened to a slide block 13,which isbest shown "in Fig. 6. This slide block may be made of suitablematerial, such as-Tlber; the-rod endsbeing attached by curved plates'l4-which'may lie-on outside of the frame'memberends and which may beattached tothe slideblock l3 by any suitable means, such as'screws I5.The slide block 13 has a' circular opening 16 to receive the post '6,'this. opening having a free-sliding with the post '6. "The slide blockis split as at ll and a bolt l8 terminatingin' a threaded portion l-Q.isius'ed for-varying the tension on the post 6 'by turning aknob20which has an interior thread 2| "engaging the threaded "end '19 of thebolt. "Thus; the adjustment of the 'knob "2% controls the-frictionbetween the slide block "I3 and the post and a 'comparativelyslight turnof this knob will. either lock the slide bloclr ln position or permit itto slide freely on thepost in adjusting the apparatus for focusing.

The; frame members 1 and 8- support'on' the parallel rails 9 a lenscarriage 22. This-lenstcarriage carries an objective 23 and mayinclude afilter 24 which may be swung axially 1to-and from the axis;.A of theenlarging apparatus. In addition; the parallel railsfl nearthe topthereof supportyan upper bellowsyframe 25, a bellows 2G conne'ctingthelens carriage '22 and'the'upper frame'25. A lamphouse Z1 which'may be ofthe construction'shown in the copending application Ser. No. 17,225,filed March'26, 1948, may rest upon the'frame'f25; brackets28;engaging'studs 29 carried byithe frame Zitdform a loose connectiontherewith, permiting a negative holder 30 to be inserted therebetween.Fortheispecific construction of the. negative'holder reference may behad to copending application Sen-"No. 137,226, filed March '26, 1948.

The lens carriage 22, as best shoWn'in'Fig; 4, is slidably mounted ontheparallelrails 9. This lens carriage includes a pair of shoes 3l-whichare notched at '32 so. .as to have a. two-point engagement with theparallel rails 9. The lens carriage 22 includes a pair of similar :andrearwardly extending hooks 34., also shownin "Fig.1,

which a shaft 35 may lie; this shaft having a attached to one end forturning the and having also, in the present instance,

erent rail-engaging members. One railengaging member 3'1 may turn on theshaft or may ith shaft 35 and may or may not be pro- .ed with a flange38. The second rail-engag- .,,embe1' is a, spool 39 having flanges 4Dwith inner walls ii inclined toward the center of the spool. Thismechanism including the cylindrical member 3'? and the spool 39, as wellas the shaft 35, are all spring-pressed tightly into contact with theparallel rails 53 by means of spring fingel-s 2 carried on the end of aplate 43 which may be attached to the lens carriage 22 as by screws d l.

Thus, the frictional engagement between the inclined walls 4! of theroller 39 causes the lens carriage 22 to be moved up and down when thefocusing knob 36 is turned so that the lens carriage may be moved on theparallel rails 23 relative to the upper bellows frame 25 and thelamphouse 27.

The upper bellows frame 25 is attached to the upper end of the rails 9in such a way that the frame 25 may be angularly tilted with respect tothe axis A'. Frame 25 carries a stud 41, as shown in Fig. this studpassing into a plate 58 which is attached by screws 49 to the upper endsof parallel rails 9. This attachment permits swiveling motion of theframe 25 when the knob is released; this knob including a shaft 5|passing through an arcuate slot 52 in the plate 33 and being carried bythe lower portion 53 of the upper bellows frame 25. Thus, if an angularposition of the negative holder 30 is required for correction fordistortion, the knob 56 is released and the upper frame 25 is swung tothe desired angle within, of course, the limits of movement permitted bythe slot 52.

The entire carriage consisting of the parallel frames 1 and 8 may bemoved up and down the column by releasing or adjusting the handwheel 20to create the proper friction upon the post 5.

This movement can be accomplished by slidin the parallel frames alongwith one hand while adjusting the knob 20 with the other. However, suchadjustment, while convenient, is not as con- Venient for fine focusingor for giving the final adjustment to the enlarger as the use of thefine adjusting mechanism which will now be described.

At the bottom of the parallel rails it), and on the side facing the post6, there is an adjusting mechanism, best shown in Fig. 3. This mechanismcomprises a shaft 60 carrying a pair of flanges 6| and 62; these flangeshaving inclined inner walls 63 and 64. While the inclination of thesewalls relative to each other may be varied, I have found that bestresults can be obtained where the included angle between the walls is inthe neighborhood of 15 because this produces a desirable frictionbetween the spool-shaped focusing wheel and the post 6. In order tofacilitate turning the spool-shaped member, I have provided flanges 65and 66 which are preferably knurled or roughened on their outer edges sothat these two wheels are convenient to an operator, one on either sideof the machine. After the quick focusing has een accomplished by movingthe slide bloc l3 up or down the post, and adjusting the lens carriage22, the final fine adjusting may be done by using either or both of theflanges 65 and G5, turning these flanges manually back and forth untilthe maximum sharpness of the image ap- 4 pears on the paper easel Ewhich is the top surface of the box-like member I or which be a surfaceon any standard type of paper older Which may be used.

The location of the spool-like focusin i just described is important. Byplaoin member on the same side of the post larging camera, the weight ofthe enl era and the frame members 1 and 8 t to rotate the focusingcamera about block [3 in the direction shown by the Fig. 2. Thismovement, of course, ho pering inner walls 63 and 8 of the fcc firmly infrictional contact with the walls and the post as the parallel moved upand down.

In order to facilitate the movement 0" cusing camera, it iscounter-balanced coiled spring 10 which, as best shown is connected to ahook H engaging a me tion 12 of the shaft and thence wardly along a wallof the post 6. A pulley mounted on a shaft '14 in the top of the poet 5,the spring passing over this pulley, thence down through the post, asindicated at 15, about a "aver pulley l6 pivotally mounted at '17 in amanner inside of the post, and thence again in a run 18 which terminatesa the spring is hooked over a support 1:, when the parallel framemembers are ed downwardly, the coiled spring counterala ces, or at leastpartially counter-balances the of the enlarging camera and therefore 11?simple matter to move the enlarging cam a up, the long coiled springassisting in this movement.

In operation, it is a simple matter to adjust the knob 20 until thefiber slide bloci ii; the post 6 with such light friction that chine maybe readily moved up and down. the proper position is reached, a partiali the knob 20 can be made to frictionally post very lightly so that thecarriage ma,- slide upon the post but will normally renia set positionbecause of the counter-b spring 10. When this friction is adjus ed rightextent, which can be very easily G01" practice, a hand-wheel or 36 maybe 1 adjust the frames for fine adjustment sin a friction between thespool-like focusing n" and the post 8 is sufficient to overcorre thefriction of the slide block. When the fin-"l 1. tion is reached, anadditional turn of tl" 1: oh 3 will firmly secure the enlargin camera e,

It is sometimes desirable to swing the focus ing apparatus so that thefocus can be obtained on some other support than the usual easel E, suchas, for instance, the floor when the enlargiIlg machine is set on atable. With my apparatus the entire enlarging apparatus be swung aboutthe post at any time by merely releasing the knob 20 and the friction onthe slide block I3 so that it turns radially about the post 6. Thespring will readily swing around with the rest of the apparatus and thenotch 51 the sliding block, as shown in Fig. 6, will guide the spring 60during this swinging movement to prevent any binding between the spring,slide block, and post.

With the focusing construction above described, a rigid and yet strongapparatus requiring but few relatively accurate tolerances can beconstructed as the frame members 7 and 8 may be of light rod or ifdesired may be of strong, light, tubular construction, as shown. It willbe nomes noticed -that the lens "carriage may-'=-f1trather looselyon theparallel-rails 9 and since only one drivin spool 39 is employed,thelocation of the second--cylindrical-member-=31 does not require anydegree ofaccuracy; Infact; the flange 38 may *bepmitted-if desired.It-should also be noticed thattheshaftfi is looselyheldby the hooks 40and held in position by the springfingers 42. The position ofthe shaftis such that the Wheel 31 and spool 39 are spring-pressed intoengagement with the parallel rails '9,-thus holding the shoes 3| inengagement with the rails on the opposite side. This construction isdesirable since it is not only inexpensive but it provides the requiredfirm contact between the inclined surfaces of the spool-focusing memberand the rail.

In spite of the relatively inexpensive construction, the above describedfocusing mechanism is light in weight, operates smoothly, and provides amechanism which can be adjusted quickly to an accurate focus by the useof the handwheel 20 alone or preferably in conjunction with one of thefocusing wheels 65 or 66.

I claim:

1. Enlarger focusin apparatus comprising a pair of spaced framesincluding parallel portions forming tracks, a bellows support carried atthe tops of the tracks, a lens board slidable upon the tracks, a pair ofparallel frame portions spaced from the tracks, a slide block at one endof said parallel portions, a post projecting vertically through theslide block, means for varying the frictional engagement between theslide block and vertical post, a flanged, spool-shaped member rotatablycarried on the ends of the parallel frame portions spaced from the slideblock and on the same side as the tracks whereby the weight of thetracks, lens board, and bellows support tends to thrust the spool-shapedmember frictlonally against the vertical post, the inner walls of thespool flanges being disposed at an angle to frictionally engage spacedwalls of the vertical post to slide the spaced frames and slide blockthereon by manually turning the spool when the frictional contactbetween the slide block and vertical post is sufiiciently reduced.

2. Enlarger focusing apparatus as defined in claim 1 characterized bythe outer peripheries of the spool flanges being of a larger diameterthan the angular disposed inner walls of the spool flanges to projectfrom the post into an accessible position for manually adjusting thespaced frame members relative to the post.

3. Enlarger focusing apparatus as defined in claim 1 characterized bythe vertical post being round in cross section, and the angular innerwalls of the spool flanges frictionally engaging spaced portions of theround post, and outer extensions on the spool flanges having a roughenedperiphery and projecting from the post for manually turning thespool-shaped member to adjust the parallel frames relative to the post.

4. Enlarger focusing apparatus as defined in claim 1 characterized bythe vertical post being round in cross section, and the angular innerwalls of the spool flanges frictionally engaging spaced portions of theround post having an included angle between them in the order of wherebysaid angular inner walls under the influence of the weight of theenlarger and track are wedged against the round section of the verticalpost.

5. Enlarger focusing apparatus comprising a pair of spaced four-sidedframes having two sides the --rails, an object-ive carried thereby, aslide bloclc moving means including a handle, a fla'nged spool engagingat least one rail, a shaft carrying the flanged spool, a spring holdingthe spool on the rail and the shoe on the track, and means at the top ofthe rails for holding a support and lamphouse against the top of therails, means for moving said post and rail-engaging spools for focusingthe enlarger, and moving the objective relative to the support andlamphouse, and both the lamphouse and support relative to the post.

6. Enlarger focusing apparatus comprising a pair of spaced four-sidedframes having two sides parallel, each frame consisting of a bent rod, aslide block, the ends of each rod being attached to the slide block, avertical post passing through the slide block, means for varying thefriction between the slide block and post, two sides of the frames beingparallel and offset from each other, by the tops and bottoms of theframes, one pair of parallel frame members constituting tracks spacedfrom the slide block for supporting a slide block, bellows, negativesupport and lamphouse, the weight of which parts is offset from theslide block tending to turn the frames thereabout, a spool rotatablycarried between the frames positioned to bear against the post andpreventing turning movement about the slide block through frictionalengagement with the post, said spool being manually rotatable to movethe frames and slide block relative to the post when friction betweenthe post and slide block are suitably adjusted, a counterbalancing coilspring connected to the frames through the spool and extending past theslide block to the top of the post, pulleys at the top of the post anddown inside of the post over which the spring passessaid sprin end beinganchored near the top of the post after passing up in the post from thelower pulley therein.

7. Enlarger focusing apparatus comprising a pair of spaced four-sidedframes having two sides parallel, each frame consisting of a bent rod, aslide block, the ends of each rod being attached to the slide block, avertical post passing through the slide block, means for varying thefriction between the slide block and post, a spool rotatably carriedbetween the spaced frames and frictionally engaging the post, two of theparallel frame sides constituting a pair of tracks, a lens carriageslidable on the rails, shoes slidably engaging the rails, means forholding the shoes on the rails comprising a shaft, spring means pressingthe shaft toward the shoes, two rollers carried by the shaft oppositethe shoes, one roller including a cylindrical portion engaging one rail,the other roller including spaced inclined flanges engaging oppositeportions of the other rail and a handle for turning the shaft andinclined flanged roller to slide the shoes over the rails for adjustingthe lens carriage thereon.

8. Enlarger focusing apparatus comprising a pair of spaced four-sidedframes having two sides parallel, each frame consisting of a bent rod,a. slide block, the ends of each rod being attached to the slide block,a vertical post passing through lens carriage, two rollers carried bythe shaft opposite the shoes, one roller including a cylindrical portionengaging one rail, the other roller including spaced inclined flangesengaging opposite portions of the other rail and a handle for turningthe shaft and inclined flanged roller to slide the shoes over the railsfor adjusting the lens carriage thereon.

JOHN H. EAGLE.

No references cited.

